Help Content > Interferometric Stacking > SBAS & E-SBAS > E-SBAS > 2

Purpose

This functionality enables to execute, in an automatic way, the following processing sequence:

–Interferogram Generation and Flattening.

–Adaptive Filter and Coherence Generation.

This step is mandatory.

Technical Note

The different steps implemented here are executed using the default processing approach (consult the reference guide specific to each processing step for more details); in particular:

•The Interferogram Flattening is performed using an input reference Digital Elevation Model or the ellipsoidal model if the DEM is not inputted; the "Geometry GCP file", if entered, is used to correct the Reference image (i.e. Super Reference acquisition of the interferometric stack) onto the Digital Elevation Model. The better the reference Digital Elevation Model accuracy/resolution the better the result in terms of topography removal. It is important to note that, in case the Super Reference image has already been corrected with the manual or the automatic procedure the GCP is not needed.

•When the Connection Graph has been executed with the "Delaunay 3D" option, the unwrapped products corresponding to the connections shown in the "Time-Position Delaunay 3D plot" are marked by the _3D_upha extension.

The data multi-looking factors are relevant to the Super Reference image. In case the input SAR series contains data with different pixel sampling (e.g. ALOS PALSAR FBS and FBD acquisitions), the program automatically changes the multi-looking factors of each interferometric pair depending on its Reference acquisition mode.

After the interferogram flattening and filtering processes can optionally be added the following optional process:

•Automatic Remove Fringe Frequency polynomial. This functionality should be used with caution, the risk is to remove and loose part of the real displacement low pass components from the interferograms and from the results.

•Automatic Remove Low Pass Fringe Frequency components. This functionality should be used with caution, the risk is to remove and loose part of the real displacement low pass components from the interferograms and from the results.

•Remove a geophysical event (like an earthquake) that implies the following E-SBAS behavior:

✍Remove of the synthesized displacement (provided with the North, Vertical and East ground surface deformation components in meters) reprojected along the Line of Sight and converted in phase, from the interferograms crossing the event date

✍Interrupt the Atmosphere High Pass Temporal filter (second inversion) across the event date

✍Add back the synthesized displacement to the final time series

To avoid loading failures it is recommended not to move any file from its original repository folder.

After the entire interferometric process has been completed, the whole E-SBAS processing folder and input file list can be moved in any disk location without compromise the further processing steps.

Tandem Bistatic are accepted and correctly managed by the program.

The Delaunay 3D functionality are under maintenance.

Input Files

Auxiliary file

Reference file generated as output of the "Connection Graph" step and possibly updated afterwards. This file is mandatory.

Optional Files

Geometry GCP file

Either a previously created Ground Control Point file (.xml) is loaded (Load GCP File) or the interface to create a new Ground Control Point file is automatically loaded (Create GCP File, refer to the ""Tools>Generate Ground Control Point" for details). This file is optional.

Optional Water Vapour File List

File list with water vapour data GACOS products (_filename_list.txt; *_bil; *_geo). When the list is initialized and compiled, the software will remove the water vapour component from the interferograms (*_clean_fint). A GACOS raster must be inserted for each input image (same date and time of acquisition). The couplings are made automatically by the software. This file is optional.

Classification Mask File

Geocoded geometry classified map, used to mask specific areas during E-SBAS processing. The masked areas will have a value of zero on the entire coherence stack and will not be considered by the unwrapping and will not be part of the final coverage map. The “Classification Mask ID List” IDs are considered as zones to be masked.

DEM/Cartographic System

Digital Elevation Model file

Digital Elevation Model file name. This should be referred to the ellipsoid. In case a list of input files is entered, the DEM must cover the whole imaged area. This file is optional.

Output Projection

In case that the Digital Elevation Model is not used, it is mandatory to define the Cartographic System.

To use the same coordinate system as another dataset, click the Import from Existing Dataset button and select the source dataset.

To apply the same Coordinate System of the current selected layer

The reset icon allows to reset the coordinate system field.

Parameters - Principal Parameters

Generate Dint Multilooked for Quick View

By setting this flag the differential interferograms, with the multilooking factors specified below, are also generated as processing outputs. These generated files only have visualization purposes and are not used for processing.

Range looks for Quick View

Number of looks in range direction (this field is active only if "Generate Dint Multilooked for Quick View" is set to TRUE). Note: Looks factor is not automatically detected.

Azimuth looks for Quick View

Number of looks in azimuth direction (this field is active only if "Generate Dint Multilooked for Quick View" is set to TRUE). Note: Looks factor is not automatically detected.

Rebuild All

By setting this flag the whole process is started from scratch. It is advisable to leave this flag unchecked in case of process interruption, so that the products already generated have not to be computed and stored again.

Atmosphere External Sensors

By inserting this optional list, the software removes the atmosphere artefacts from the filtered interferogram stack using external sensors such as GACOS and MERIS (only for ENVISAT data).

Coregistration With DEM

By setting this flag, the input Digital Elevation Model is used in the coregistration process.

Parameters - Cluster

It brings to the cluster section of the Preferences parameters. Any modified value will be used and stored for further processing sessions.

Parameters - Global

It brings to the general section of the Preferences parameters. Any modified value will be used and stored for further processing sessions.

Parameters - Interferogram

It brings to the interferometry section of the Preferences parameters. Any modified value will be used and stored for further processing sessions.

Parameters - Flattening

It brings to the flattening section of the Preferences parameters. Any modified value will be used and stored for further processing sessions.

Parameters - Atmosphere

It brings to the atmosphere and general section of the preferences parameters. Any modified value will be used and stored for further processing sessions.

Parameters - Other Parameters

It brings to the general section of the Preferences parameters. Any modified value will be used and stored for further processing sessions.

Process_str

This parameter does not have any impact on the processing chain.

Range Looks

This look factor is used as oversampling which is applied to input SLC before the creation of interferograms according to Nyquist.

Azimut Looks

This look factor is used as oversampling which is applied to input SLC before the creation of interferograms according to Nyquist.

Generate Dint Multilooked for Quick View

Range looks for Quick View

Number of looks in range direction (this field is active only if "Generate Dint Multilooked for Quick View" is set to TRUE). Note: Looks factor is not automatically detected.

Azimuth looks for Quick View

Number of looks in azimuth direction (this field is active only if "Generate Dint Multilooked for Quick View" is set to TRUE). Note: Looks factor is not automatically detected.

Interpolation Type

By setting the relevant flag, the interpolation type is specified.

Nearest Neighbour

Bilinear Interpolation

3rd Order Cubic Convolution

4th Order Cubic Convolution

Keep Coregistration Ancillary Info

Store the coregistation windows parameters in .xls files in the E-SBAS working folder.

Rebuild All

Output Files

interferogram_stacking folder

Directory containing the following products:

•Due to the large number of output products meta (_meta). files are generated. They enable to load at once all relevant output products:

•The “interf_tiff” sub-folder with the tiff files of intermediate interferometric E-SBAS results.

Generated meta:

•slant_dint_meta: which refers to all .dint files in slant range geometry.

•slant_pwr_meta: which refers to all slant range power images.

In case the Generate Dint Multilooked for Quick View is set to True, a folder including all the tiff files "tiff_multilooked_dint" will be created. A metafile "slant_multilooked_dint_meta" will be created in the interferogram_stacking as well.

In order to distinguish the input SAR pair where each output product comes from (as well as to identify it in the connection network), a prefix containing the Reference-Secondary acquisition dates (i.e. yyyymmdd) and the Reference-Secondary relationships will be added.

Details specific to the Units of Measure and Nomenclature of the output products can be found in the Data Format section.

General Functions

Exec

The processing step is executed.

Store Batch

The processing step is stored in the batch list. The Batch Browser button allows to load the batch processing list.

The window will be closed.

Help

Specific help document section.

Specific Function(s)

None.

Interferometric Stacking - SBAS & E-SBAS - E-SBAS - Intereferometric Process

Interferometric Stacking - SBAS & E-SBAS - E-SBAS - Intereferometric Process